weeping fig tree (Ficas)

My tree has been in the same place since I received it over two years ago. Soon after arriving at its new home it did the "shedding" ritual, but it came back beautifully! Now the back branch died,(like half of the tree) all the leaves were dry, and the branch just snapped off. A local florist had recommended pruning the "dead" part off. What would cause this and what do I do with it now? The rest of the tree has new growth and seems to be thriving.Thanks in advance,Melanie